<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>flex-flow</title>
    <style type="text/css">
        /*
        flex-flow:<flex-direction> || <flex-wrap>;
        flex-flow属性是flex-direction属性和flex-wrap属性的简写形式，默认值为row nowrap
        */
        .unit{
            width: 80px;
            height:50px;
            background:orange;
            margin:10px;
        }
        .box{
            display: flex;
            flex-flow:row wrap;
            width: 500px;
            height:150px;
            border:1px solid #000;
            margin:10px;
        }
    </style>
</head>
<body>
<div class="box">
    <div class="unit">1</div>
    <div class="unit">2</div>
    <div class="unit">3</div>
    <div class="unit">4</div>
    <div class="unit">5</div>
    <div class="unit">6</div>
    <div class="unit">7</div>
    <div class="unit">8</div>
    <div class="unit">9</div>
</div>
</body>
</html>
